A circuit interrupter is an electrical component that can break an electrical circuit, interrupting the current. A basic example of a circuit interrupter is a switch, which generally consists of two electrical contacts in one of two states; either closed, meaning the contacts are touching and electricity can flow between them, or open, meaning the contacts are separated. A switch may be directly manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit, such as a light switch.
A second example of a circuit interrupter is a circuit breaker. A circuit breaker is used in an electrical panel that monitors and controls the amount of amperes (amps) being sent through the electrical wiring. A circuit breaker is designed to protect an electrical circuit from damage caused by an overload or a short circuit. If a power surge occurs in the electrical wiring, the breaker will trip. This will cause a breaker that was in the “on” position to flip to the “off” position and shut down the electrical power leading from that breaker. When a circuit breaker is tripped, it may prevent a fire from starting on an overloaded circuit; it can also prevent the destruction of the device that is drawing the electricity.
A standard circuit breaker has a line and a load. Generally, the line is the incoming electricity, most often from a power company. This can sometimes be referred to as the input into the circuit breaker. The load, sometimes referred to as the output, feeds out of the circuit breaker and connects to the electrical components being fed from the circuit breaker. There may be an individual component connected directly to a circuit breaker, for example only an air conditioner, or a circuit breaker may be connected to multiple components through a power wire which terminates at electrical outlets.
A circuit breaker can be used as a replacement for a fuse. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Fuses perform much the same duty as circuit breakers, however, circuit breakers are safer to use than fuses and easier to fix. If a fuse blows, oftentimes a person will not know which fuse controls which specific power areas. The person will have to examine the fuses to determine which fuse appears to be burned or spent. The fuse will then have to be removed from the fuse box and a new fuse will have to be installed.
Circuit breakers are much easier to fix than fuses. When the power to an area shuts down, the person can look in the electrical panel and see which breaker has tripped to the “off” position. The breaker can then be flipped to the “on” position and power will resume again. In general, a circuit breaker has two contacts located inside of a housing. The first contact is stationary, and may be connected to either the line or the load. The second contact is movable with respect to the first contact, such that when the circuit breaker is in the “off”, or tripped position, a gap exists between the first and second contact.
The problem, with circuit interrupters, is that even though it may be in the open position, i.e. a switch is open or a circuit breaker has tripped, interrupting the connection, the open area between the first and second contact allows an electrical arc to form between the two contacts. The electrical arc is the residual electricity and may have a high voltage and amperage. Arcs can be dangerous as they can cause damage to the circuit interrupter, specifically damaging the electrical contacts. Any damage to the electrical contacts shortens the lifespan of the circuit interrupter, and affects its performance. It is therefore very important to cool and quench the arc quickly to prevent damage to the circuit interrupter.
There have been many proposed devices to quickly quench an arc. For example, U.S. Pat. No. 5,731,561 to Manthe et al. discloses a device with a sealed arc chamber. Inside of the sealed arc chamber is a gas designed to quench the arc that is formed when the circuit breaker trips. A disadvantage of this device is that is expensive to produce. The circuit breaker requires a sealed chamber, which is expensive to manufacture and test, and also requires a specific, arc quenching, gas. The combination of the sealed chamber and the gas make this device very expensive. Additionally, any leaks in the chamber will cause a leak in the gas, preventing any quenching from taking place.
U.S. Pat. No. 6,717,090 to Kling et al. discloses a device with an arc splitter stack into which the arc passes via guide rails. A disadvantage of the device proposed in Kling is that is does not rapidly quench the arc. While providing some quenching using the arc splitter, the arc splitter alone does not provide enough cooling to quickly quench the arc.
What is desired therefore is a circuit interrupter that can quickly cool and quench an arc, that is inexpensive to produce, and provides rapid cooling to protect the electrical contacts in the circuit interrupter.